The biosynthesis pathway for the conversion of farnesyl pyrophosphate to squalene is being investigated. Attention has been focused on the structural features of farnesyl pyrophosphate I that are a prerequisite for substrate recognition. Analogues of I have been prepared and are being studied to elucidate this information. Attempts are being made to develop effective inhibitors for the synthetase. Similarly, analogues of presqualene pyrophosphate II are being prepared to ascertain the mechanism by which II is converted to squalene. To confirm the absolute configuration assigned to II the synthesis of optically active presqualene alcohol of known chirality has been undertaken.